So this is where VAR can and will be use corruptly.
Offside as you say, is not black and white. If the view of the pass is obscured, then the VAR officials are making a judgement call as to whether or not the attacker was offside or not at the very point the pass was made. Given the speed some players run at we are not talking millimetres of error, more like meters. So there is one instance conscious/unconscious bias can be an effect in the outcome of a decision. - completely agree with this - maybe there needs to be a new definition of offside (eg clear daylight between defender and attacker for it to be offside - maybe this would make up the room for error)
In the instance of the third goal that never was, it was the defenders actions (drag back) which caused Laport's arm to be in the position where he made contact with the ball. The ball also hit the defenders arm practically simultaneously, but apparently that's ok even though his action of pulling back Laport's arm was not accidental. At the least it should have been a foul against Spurs. Even with my blue tinted spec's off, I can see that kind of decision going the other way for another team this season in the PL.
It doesnt hit the defneders arm, it comes off Laportes
The pulling back comes before the action of heading not duinrg..if you know anything you would know when you jump you raise your arms naturally (and this is what always got me frustrated previously with people saying a defneders arms should be up there when jumping...actually they should be raised as its completely natural to do so for balance and propulsion)
you could argue it could have been a foul - and sometimes they are given and sometimes not - just like the other foul where someone dragged at (Laportes?) arm in an earlier inciden while we were still 2-1 up) - sometimes they are given, sometimes not.
VAR should take away any doubt, but unfortunately it adds ANOTHER LAYER OF (UNACCOUNTABLE) SUBJECTIVITY TO THE APPLICATION OF THE LAWS OF THE GAME.